The present invention relates to an equipment for the adjustment of the length of a support, especially for chairs, tables or the like, with one essentially tubular interior part and with a piston which is supported in the interior part in a fluid tight manner, and a process for the manufacturing of this equipment.
An equipment of this type is already known. That end portion of a piston rod, which is placed in the interior of the casing of this equipment, has a circumferential step so that the end portion of the piston rod has the form of a pivot. The main body of the piston is put on said pivot, whereby this main body has the form of a flat ring. In the peripheral wall of the piston main body a circumferential groove is carried out, in which a first sealing ring lies. This ring seals in a fluid tight manner the gap between the piston main body and the inside wall of the casing. In the cylindrical side wall of the pivot, a second groove is carried out in which a second sealing ring is placed. This second ring seals in a fluid tight manner the gap between the side wall of the pivot and the side wall of the opening in the piston main body.
Among other things the fact is regarded as disadvantageous of this known construction of the prior equipment that the piston arrangement consists of several components which must be assembled during the manufacturing of this equipment.
The object of the present invention is to eliminate these and further disadvantages of the prior art.
This object is achieved according to the present invention in the case of the equipment of the generic type mentioned in the introduction as defined in the characterising part of the patent claim 1.
A process for the manufacturing of this equipment is according to the present invention defined in the characterising part of the patent claim 10.